Bombus bellicosus has not yet been evaluated for the IUCN Red List of Threatened Species. It is a very rare bumblebee native to southern Brazil, Uruguay and northern Argentina. The species, previously widespread across southern Brazil’s grasslands, has been declining since the 1960s, likely due to habitat conversion and climate change.
B. bellicosus is thought to have become locally extinct in the Brazilian state of Paraná, where it used to be relatively abundant. Urban development has destroyed much of the native grass meadows in the area, leading to the species’ local disappearance. Females of B. bellicosus cover their nest cavity with an insulating waxy layer, which is probably an adaptation against low temperatures. This trait is unique among tropical and subtropical bumblebees, and researchers believe this waxy layer may become a hazard to B. bellicosus broods under future climate change, which will likely lead to further range contractions.
There are no conservation measures in place yet for this species, but effective habitat protection will be required to save it from extinction. An IUCN Red List assessment of B. bellicosus will improve understanding of its habitat needs and the drivers of its decline, which will help to guide suitable conservation measures for the future.